Characteristics of a modern in/out architecture

摘要

The performance characteristics of modern high end commercial systems are to a significant extent determined by their In/Out (I/O) architecture. Here zSeries and S/390 computers feature a large number of leading edge characteristics not (yet) available on other systems. Among these are the Channel Subsystem, which executes I/O related code concurrently with the CPU, the capability to access a disk alternatively over several parallel paths, or priority controls which permit a work load manager to reassign I/O resources dynamically in response to changing work load situations. The following paper provides an overview of modern I/O characteristics which are implemented on S/390 and zSeries systems and their relationship to the forthcoming InfiniBand standard.